Keep in mind only the U-235 isotope is fissionable, which comprises less than 1% of the total uranium, and there is more nuclear energy potential in the isotopes of hydrogen (fusion power) in sea water.

Deuterium is even MORE plentiful in seawater than is Uranium.

Deuterium has an abundance of about 0.015% relative to all Hydrogen. Water is 2/18 or about 11% Hydrogen.

Therefore water is about 0.0000167 Deuterium = 1.67e-5 Deuterium or 16,700 parts per billion. Uranium is about 3 parts per billion in seawater, and the fissile U-235 is 0.7% of that.

Additionally, you get more energy per unit mass in fusion than in fission. Fission gives you about 1 MeV / amu. Fusion gives you about 3.5 MeV/amu.

So the fusion energy content of the Deuterium in seawater represents almost 3 MILLION TIMES as much energy as the fission energy content of the U-235!

Fritz Haber thought he could help pay off Germany's crushing war debt from WW I by extracting gold from seawater. It wasn't enough that he fertilized the Green Revolution, helping to feed untolled billions. The gold extraction went nowhere, as I think uranium from sea water will. Why bother when there's thorium to be had?

I have a better idea, How about we take the nuclear waste from the power and medical industries, and collect it in one place. We could call it, for example, say, "Yucca Mountain". Why I bet we won't run out of it for 10's of thousands of years, and even without a study, I bet the concentration would be better than 3 parts in a billion :)

oh wait, Obama's NRC chairman, Harry Reid's chump used extra-legal means against the wishes of the NRC professional staff and the other board members to dismantle the Yucca mountain plans and existing infrasture, so that no future adminstration could easily restart the effort.

Shrimp shells can also be used to make delicious beurre de crustacés, basically butter pounded in a mortar (or more easily, whizzed in a food processor) with the shells and other shrimp debris, then passed through a fine-meshed sieve.

A more practical use for the shells, and far better on sandwiches than uranium.